Theres a linear relationship between impressions and likes, likes increase as impressions increase
Theres no relation between impressions and comments
A more number of shares will result in a higher reach, but shares don’t affect the reach of a post as much as likes do
Theres a linear relationship between Impressions and Saves
So we can say that more likes and saves will help you get more reach on Instagram. The higher number of shares will also help you get more reach, but a low number of shares will not affect your reach either.
In Instagram, conversation rate means how many followers you are getting from the number of profile visits from a post.

Instagram Reach Prediction Model